Download or read book Magnetic Anisotropy and Its Microstructural Origin in Epitaxially Grown SmCo Thin Films written by and published by . This book was released on 1998 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microstructural features and magnetic behavior of epitaxially grown SmCo thin films with very high in-plane anisotropy are presented. Transmission electron microscopy was used to characterize the microstructure while magnetic measurements were performed using dc and SQUID magnetometers. Two substrate orientations were studied, i.e., MgO(100)/Cr(100)/SmCo(11{bar 2}0) and MgO(110)/Cr(211)/SmCo(1{bar 1}00). In the former, the SmCo(11{bar 2}0) film shows a bicrystalline microstructure, whereas in the latter, a uniaxial one is observed. Both microstructure consist of grains with a mixture of SmCo3, Sm2Co-- and SmCo3 polytypoids. A deviation from the c-axes was observed in the in-plane anisotropy of the SmCo(11{bar 2}0) thin film. A strong exchange interaction between the grains would, in principle, explain the observed deviation. On the other hand, both SmCo(11{bar 2}0) and (1{bar 1}00) thin films show very high coercivity values with pinning-type characteristics. Possible coercivity mechanisms related to intergranular exchange interactions and local variation in magnetocrystalline anisotropy constants are discussed.
Download or read book Crystal Structure Anisotropy and Spin Reorientation Transition of Highly Coercive Epitaxial Pr Co Films written by Ajit Kumar Patra and published by Cuvillier Verlag. This book was released on 2008 with total page 115 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Magnetic and Microstructural Properties of Sputter deposited Amorphous CoSm Thin Films written by Yukiko Kubota and published by . This book was released on 1998 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Magnetic Anisotropy in Epitaxial Ni Cu 001 Thin Films and Cu Ni Cu 001 Sandwiches written by Gabriel Bochi and published by . This book was released on 1995 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Digests of Intermag written by and published by . This book was released on 1998 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Epitaxial Sm Co Thin Films written by and published by Cuvillier Verlag. This book was released on 2007-01-05 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Chemical Abstracts written by and published by . This book was released on 2002 with total page 2626 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Strain Engineering of Magnetic Anisotropy written by David Michael Carr and published by . This book was released on 2004 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Investigation of Epitaxially Grown Magnetic Nanostructures written by Jun Woo Choi and published by . This book was released on 2008 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Magnetic Characterization of 001 and 111 Ni Films Epitaxially Grown on MgO written by R. A. Lukaszew and published by . This book was released on 2001 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: One interesting application of epitaxial magnetic thin films is to use them as one of the electrodes in a spin-dependent tunneling junction in order to use the magnetocrystalline anisotropy to define the required two states of the magnetization. (1) In our preliminary work we prepared epitaxial magnetic films on copper buffer layers grown on silicon substrates. (2) The single crystalline quality of the films was particularly evident in the magnetization hysteresis loops showing a sharp reversal at fairly high fields (120 Oe) when the samples were magnetized along the crystallographic easy axis. One technological disadvantage in this type of samples is the chemical interaction between the metallic layers and the silicon substrate. In order to explore the possibility of epitaxial magnetic films on less reactive substrates we studied the growth on MgO substrates. We have shown that it is possible to obtain epitaxial (001) and (111) Ni films grown on MgO substrates. 3 In particular we observed that the crystalline quality of the films improved considerably after 10 run of film growth. We will now present our studies on the magnetic properties of these films particularly the azimuthal dependence of the magnetization reversal using MOKRE correlating our finding with the structural characterization obtained with RHEED, STM and XRD.
Download or read book Micromagnetics and Microstructure of Epitaxially Grown Co and Co Cr Films Suitable for Perpendicular Magnetic Recording written by and published by . This book was released on 1994 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: Highly c-axis oriented, single crystal films of Co{sub 1-x}Cr(subscript x) (0(less-than or equal to) x (less-than or equal to) 0.3) have been grown epitaxially on mica substrates by e-beam evaporation. Films grown on Ru underlayers have an average grain size of 50--80nm, negligibe fcc content and very narrow c-axis dispersions. For Co films (x=0), the as-grown magnetization structure are mainly 180° domain walls with a uniform distribution of cross-ties for thinner samples ((less-than or equal to) 300Å), whilst thicker (>400Å) ones show stripe domains. These images were analysed in detail to measure that wall widths and associated energy densities for as-grown, remanent and ac- magnetised samples. As expected, the magnetic properties of these films are composition dependent. However, for any Cr concentration, these films exhibit the largest saturation magnetisation when compared with either sputtered or evaporated samples. This enhancement can be attributed to a nanometer-scale segregation of Cr, which in these samples, which in these samples, could be particularly aided by the diffusion on the close-packed planes of the films with very narrow c-axis dispersions. Preliminary X-ray microanalysis and NMR data support this interpretation.
Download or read book Influence of the Epitaxial Strain on Magnetic Anisotropy in LSMO Thin Films for Spintronics Applications written by Sandeep kumar Chaluvadi and published by . This book was released on 2017 with total page 161 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report a quantitative analysis of thickness dependent epitaxial strain-induced effects in La1-xSrxMnO3 (LSMO) (001) (x = 0.33) thin films of thicknesses (50, 25 and 12 nm) grown on various single crystal substrates such as SrTiO3 (STO) (001), STO buffered MgO (001), NdGaO3 (NGO) (110) and (LaAlO3)0.3(Sr2AlTaO6)0.7 (LSAT) (001) by Pulsed Laser Deposition (PLD) technique. We also report the composition dependent magnetic properties of LSMO thin films with x = 0.33 and 0.38 in particular grown onto LSAT (001) substrate by Molecular Beam Epitaxy (MBE). The study mainly includes measurements such as X-ray Diffraction (XRD), Atomic Force Microscopy (AFM), temperature dependent four-probe resistivity, magnetization properties by Superconducting Quantum Interference Device (SQUID), magnetic anisotropy by Magneto-Optical Kerr Magnetometry (MOKE). Our results highlight the detailed study of angular evolution and thickness dependent magnetic anisotropy, remanence, coercivity and switching field in epitaxial LSMO thin films. Temperature-dependent studies are also performed on few selected films. We will also discuss the cause of magnetic anisotropy in LSMO films i.e., magneto-crystalline and magnetostriction anisotropy and the effects of steps or substrate mis-cut induced anisotropy.
Download or read book The Magnetic and Chemical Structural Property of the Epitaxially grown Multilayered Thin Film written by Hwachol Lee and published by . This book was released on 2012 with total page 127 pages. Available in PDF, EPUB and Kindle. Book excerpt: L10 FePt- and Fe-related alloys such as FePtRh, FeRh and FeRhPd have been studied for the high magnetocrystalline anisotropy and magnetic phase transition property for the future application. In this work, the thin film structural and magnetic property is investigated for the selected FePtRh and FeRhPd alloys. The compositionally-modulated L10 FePtRh multilayered structure is grown epitaxially on a-plane Al2O3 with Cr and Pt buffer layer at 600degC growth temperature by DC sputtering technique and examined for the structural, interfacial and magnetic property. For the epitaxially grown L10 [Fe50Pt45Rh5 (FM) (10nm) / Fe50Pt25Rh25 (AFM) (20nm)]×8 superlattice, the magnetically and chemically sharp interface formation between layers was observed in X-ray diffraction, transmission electron microscopy and polarized neutron reflectivity measurements with the negligible exchange bias at room and a slight coupling effect at lower temperature regime. For FeRhPd, the magnetic phase transition of epitaxially-grown 111-oriented Fe46Rh48Pd6 thin film is studied. The applied Rhodium buffer layer on a-plane Al2O3 (1120) at 600degC shows the extraordinarily high quality of epitaxial film in (111) orientation, where two broad and coherent peak in rocking curve, and Laue oscillations are observed. The epitaxially-grown Pd-doped FeRh on Pt (111) grown at 600degC, 700degC exhibits the co-existing stable L10 (111) and B2 (110) structures and magnetic phase transition around 300degC. On the other hand, the partially-ordered FeRhPd structure grown at 400degC, 500degC shows background high ferromagnetic state over 5K~350K temperature. For the reduced thickness of Fe46Rh48Pd6, the ferromagnetic state becomes dominant with a reduced portion of the film undergoing a magnetic phase transition. For some epitaxial FeRhPd film, the spin-glass-like disordered state is also observed in field dependent SQUID measurement. For the tri-layered FeRhPd with thin Pt spacer, the background ferromagnetic state is significantly reduced and spin-glass-like state also disappears. In polarized neutron reflectivity, magnetic depth profiles of tri-layered FeRhPd reveals the asymmetric magnetization between two FeRhPd layers. The asymmetric magnetic profile of FeRhPd tri-layered structure is closely related to the thickness dependent epitaxial film growth of B2 structure.
Download or read book Structure and Properties of Co based Thin Films and Multilayers with Perpendicular Magnetic Anisotrophy written by Grzegorz Jan Kusinski and published by . This book was released on 2001 with total page 530 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Competing Anisotropies in Epitaxial Exchange Biased Thin Films and Patterned Nanostructures written by Wei Zhang and published by . This book was released on 2013 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetization reversal properties in thin-films and patterned nanostructures are essential for various modern magnetic devices. The magnetization reversal is determined by the magnetic anisotropies of the system, which can come from different origins. Specifically, the exchange bias, also known as the exchange anisotropy, brings in a shift of the magnetic hysteresis loop which has been widely applied in magnetic recording technologies and magnetic sensors. In an exchange bias system, other types of magnetic anisotropies, such as the magnetocrystalline anisotropy or the shape anisotropy, can be present and interacts with the exchange anisotropy thus affecting the magnetic reversal cooperatively. In order to study the competing magnetic anisotropies in the exchange bias system, we have developed approaches to grow epitaxial exchange-biased ferromagnetic-antiferromagnetic thin-film bilayers, which bring significant magnetocrystalline anisotropy into the exchange bias system. We studied the magnetization reversal of these bilayers using magneto-optic Kerr effect and anisotropic magnetoresistance, and investigated systematically the dependence of magnetic anisotropies on various sample parameters, including layer thickness, temperature, relative orientation, interfacial spin behavior, and the antiferromagnetic bulk structure. To explain the samples' unique magnetic behaviors, we developed a quantitative model based on magnetic domain-wall nucleation and propagation process, and offered a consistent and integrated interpretation on the magnetic reversal properties. To further incorporate the shape anisotropy into the exchange bias system, we developed a large-area, efficient epitaxial patterning process using nanoimprint lithography, which allows us to pattern epitaxial magnetic thin-film bilayer and multilayers into nanostructures. By combining the bilayer-resist template and Molybdenum liftoff, we are able to create high-quality, patterned structures with different sizes ranging from ~ 70 nano-meter to ~ 5 micro-meter. The magnetization reversals, especially the domain-wall structures during the reversal, are subsequently studied by hysteresis loop measurements and direct imaging techniques. Finally, in addition to fundamental studies on the magnetic reversal, the nanoimprint processes developed for this thesis can also find great potential in relevant industries.
Download or read book Substrate and Growth Related Microstructural and Magnetic Properties in La sub 0 67 Sr sub 0 33 MnO3 Thin Films written by and published by . This book was released on 1998 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ambient observation of magnetic domain structures by magnetic force microscopy (MFM) in La{sub 0.67}Sr{sub 0.33}MnO3 films has not yet been clearly correlated with stresses induced by kinetic or thermodynamic growth processes or the compressive (LaAlO3) or tensile (SrTiO3) nature of the film-substrate lattice mismatch. Although domain-like magnetic structures have been seen in some as-grown films and related to substrate-induced stress and film thickness, no magnetic structure has been seen for other films grown under similar conditions on the same pair of substrates. In this study the authors have grown films over a range of temperatures by pulsed-laser deposition, using the above substrates, to determine the relationship between growth and stress-induced magnetic structures. Results from scanning tunneling, atomic force, and magnetic force microscopies, measurements of temperature-dependent magnetization and structure-dependent coercivity show the relationship between growth and magnetic properties. Maze-like domain structures, with separations between 150 nm and 200 nm, were only observed for the thicker films grown at the highest temperature, 800 C. Application of an in-plane magnetic field converted these domain structures to stripe-like domains whose spacing and out of plane component decreased as the field was increased.
